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Trailing shoe reduces N bills on grazing

Trailing shoe reduces N bills on grazing

Applying slurry to dairy cow grazing ground in summer using a trailing shoe applicator can replace up to 150kg N/ha, according to trials at AFBI, Hillsborough, funded by AgriSearch.

Dr Andrew Dale and colleagues found no effect on cow grazing behaviour or milk production in studies replacing 80kg of bagged N/ha with two applications of slurry (31 and 19m3/ha).

A second study replaced 150kg/ha of bagged N with four slurry applications (40, 27, 28 and 19m3/ha), at two grazing intensities. This found that at normal intensity grazing to a 6cm residual there was no effect on cow performance, but with tight grazing to 5cm there was a 1kg/cow reduction in milk yield.

Andrew concludes that clearly under normal grazing management slurry could be applied to replace up to 150kg N/ha, saving £44/ha in fertiliser (based on CAN at £240/t).

However, care is needed to avoid oversupply of phosphate to the grazing area, he warns.